Composition for eliminating thermosetting resin

ABSTRACT

A composition suitable for eliminating a thermosetting resin (and a method of so using the composition) is disclosed. In the composition, tetra methyl ammonium hydroxide (TMAH) is included so as to eliminate the thermosetting resin. Accordingly, the composition is suitable for removing a dielectric layer, an organic protective layer, an insulating layer, an alignment layer, black matrices and color filters, etc. made form a thermosetting resin in an LCD or a semiconductor, and permits a reproduction or a rework of the thermosetting resin film.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a composition suitable for eliminatinga thermosetting resin, and a thermosetting resin eliminating apparatususing the same.

[0003] 2. Description of the Related Art

[0004] Generally, an active matrix liquid crystal display (LCD) uses athin film transistor (TFT) as a switching device to display a movingpicture. Since the LCD is able to provide a product having a smallerdimension than a Cathode Ray tube, it has been widely used in variousapplications including personal computer, notebook computer, officeautomation equipment such as a copy machine, etc., and portableequipment such as a PDA and a pager, etc.

[0005] Such an LCD typically uses a thermosetting resin such aspolyimide, polyacrylate or benzocyclobutane, etc. as a material of adielectric layer, an organic protective layer, an insulating layer, analignment film, a black matrix and a color filter. However, this film orlayer formation using said thermosetting resin raises a problem of adifficult stripping process. Thus, if a problem occurs with a film orlayer made from a thermosetting resin in a process of manufacturing anLCD or a semiconductor, then the film or layer has been often discardedbecause of a difficulty of rework or reproduction. In order to preventsuch a loss, a rework process for each process has been developed.

[0006]FIG. 1 and FIG. 2 shows a method of forming color filters step bystep. Referring to FIG. 2, at step S1, Cr/CrO_(x) or Cr/CrN_(x)/CrO_(x)is entirely deposited on a bare glass substrate 2 and thereafterpatterned. Then, black matrices 4 are formed on the bare glass substrate2 at step S2. Alternatively, the black matrices 4 made from a resin maybe formed by entirely coating polyacrylate added with a black pigment onthe bare glass substrate 2 and thereafter patterning it.

[0007] As a result of testing the black matrices 4 formed in thismanner, if it is judged that a problem exists with the black matrices 4,a process of reworking the black matrices 4 is carried out at step S3.Herein, since the black matrices 4 are made from a thermosetting resinand because it is impossible to completely eliminate a thermosettingresin, black matrices made from a metal only is introduced into therework process. After the black matrices 4 are formed, red, green andblue color filters 16R, 16G and 16B are sequentially formed on thesubstrate 2 at steps S4 to S6.

[0008] First, as shown in FIG. 1, a red resin 6 is entirely coated onthe substrate 2 and then a photo mask pattern 8 is formed thereon. Next,the red resin 6 made from polyacrylate is patterned by an exposure anddevelopment process. Subsequently, the green filter 16G and the bluefilter 16B are formed in the same manner. Since the color filters aremade from a thermosetting resin that cannot be eliminated completely, arework process is almost impossible. Finally, after the color filters16R, 16G and 16B were formed, indium tin oxide (ITO) used as a commonelectrode is entirely deposited thereon (step S7).

[0009] In order to eliminate a thermosetting resin, a dry etching methodis generally used. For instance, the substrate on which a thermosettingresin is formed into a film is mounted in a chamber to inject O₂,O₂+Cl₂, CF₄ or SF₆, etc. into the chamber, thereby generating a plasmadischarge. Then, a reaction between said injection gas and saidthermosetting resin film occurs to entirely etch the thermosetting resinfilm. However, said dry etching method has various problems includingimperfection in a post process such as a pattern badness and anelectrical short badness, etc. Such problems are caused by an aliensubstance left at the surface after the thermosetting resin film waseliminated. For example, an under layer of the thermosetting resin filmis damaged upon over-etching.

[0010] An alternative scheme for eliminating a thermosetting resin is amethod of solving a problem of said dry etching and an ashing using anO₂ plasma and taking advantage of a stripper of a stripping liquid so asto obtain a dry cleaning effect. However, since the known strippers caneliminate only a thermosetting resin of a specific material, forexample, an alignment film (i.e., polyimide, etc.) of an LCD, its usehas been limited. Some example stripper compositions are listed in Table1 and Table 2.

[0011] Strippers for eliminating color filters having a compositionindicated by the following Tables 1 and 2 are capable of eliminating ablue resin or blue and green resins, but are incapable of eliminating ared resin. As a practical matter, it is difficult for such strippers toeliminate a blue resin. This is caused by a fact that, since coating andpatterning of a resin followed by a high-temperature curing process arerepeatedly carried out in a sequence of a red resin, a green resin and ablue resin are repeated in the color filter formation process, a greenresin and a red resin are over-cured in comparison to a blue resin.TABLE 1 Composition of stripper A Mono Ethanol Amine  1.97% MethylCarbitor  6.97% Benzyl Alcohol 10.87% NMP 11.28% Diethyl CARBITOL 11.19%1,3-Dimethyl-2-imidazolidone 12.32% Water  45.4%

[0012] TABLE 2 Composition of stripper B Methanol  2.07% Mono EthanolAmine  6.54% 2-Ethylhexanol 32.09% Water  59.3%

SUMMARY OF THE INVENTION

[0013] Accordingly, it is an object of the present invention to providea composition suitable for eliminating a thermosetting resin.

[0014] Another object of the present invention is to provide anapparatus suitable for eliminating a thermosetting resin on a substrateusing the composition.

[0015] In order to achieve these and other objects of the invention,there is (in part) provided a composition for eliminating athermosetting resin (and a method of so using the composition), thecomposition comprising: tetra methyl ammonium hydroxide (TMAH); water;and a hygroscopic resin solvent. The hygroscopic resin solvent can beCARBITOL. A component ratio of the composition can be TMAH in a range ofabout 7-10 wt % and CARBITOL at about 50 wt %. Also, water can bepresent in a range of about 43-40 wt %, respectively, relative to saidTMAH. As a more specific component ratio, TMAH can be in a range ofabout 7-8 wt % and water in a range of about 43-42 wt %, respectively,relative to said TMAH; or TMAH can be about 10 wt % and water about 40wt % relative to said TMAH. The water can be de-ionized water.

[0016] The invention, in part, also provides a thermosetting resineliminating apparatus includes: a unit to strip a substrate with any oneof an dielectric layer, an organic protective film, an insulating layer,an alignment film, a black matrix and a color filter which are made froma thermosetting resin, the substrate being dipped into a compositionsuch as described above; and a unit to mechanically clean the strippedsubstrate using water, preferably de-ionized water.

[0017] Advantages of the present invention will become more apparentfrom the detailed description given hereinafter. However, it should beunderstood that the detailed description and specific examples, whileindicating preferred embodiments of the invention, are given by way ofillustration only, since various changes and modifications within thespirit and scope of the invention will become apparent to those skilledin the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus do not limit thepresent invention.

[0019]FIG. 1 is a section view showing a conventional color filtermanufacturing method step by step;

[0020]FIG. 2 is a flow chart representing a procedure of theconventional color filter manufacturing method;

[0021]FIG. 3 is a schematic block diagram showing a configuration of athermosetting resin removing apparatus according to an embodiment of thepresent invention;

[0022]FIG. 4 is a flow chart representing a color filter rework processaccording to an embodiment of the present invention; and

[0023]FIG. 5 is a flow chart representing a color filter rework processaccording to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] A composition for eliminating a thermosetting resin according tothe present invention includes tetra methyl ammonium hydroxide (TMAH),water and a hygroscopic resin solvent such as CARBITOL. An examplecomponent ratio is listed in (following) Table 3. TABLE 3 SubstanceComponent (wt %) 20% TMAH Solution 50 CARBITOL 50

[0025] In the Table 3, 20% TMAH solution means that about 20 wt % TMAHis added to de-ionized water. In other words, an example component ratiofor the thermosetting-resin-eliminating composition according to theinvention is a mixture including TMAH and CARBITOL having the particularformulation of about 10 wt % TMAH, about 40 wt % water and about 50 wt %CARBITOL in consideration of water. Though a preferred component ratiois TMAH at a weight ratio of about 10 wt %, but the TMAH component canalso be present in an amount as low as a weight ratio of about 7 to 8 wt%. It is noted that another name for CARBITOL is D(ethyleneglycol)-ethyl-ether.

[0026]FIG. 3 shows a thermosetting resin eliminating apparatus employinga composition for removing a thermosetting resin according to anembodiment of the present invention. Referring to FIG. 3, thethermosetting resin eliminating apparatus includes a dipping unit 12connected in series, and a physical/mechanical cleaning unit 14. Thedipping unit 12 includes a vessel or tub containing with a compositionhaving a component ratio as indicated by the above Table 3.

[0027] The dipping unit 12 is fed with a substrate 10 provided with adielectric layer, an organic protective layer, an insulating film, analignment film, black matrices or color filters which are made from athermosetting resin and have an imperfection. This substrate 10 isdipped into a composition that includes TMAH and CARBITOL as indicatedby the Table 3 for a desired time by way of the dipping mechanism (notdepicted).

[0028] Then, the CARBITOL separates the thermosetting resin layer fromthe substrate 10 or the under layer film. And the TMAH separatesparticles of the thermosetting resin layer from each other.

[0029] At the substrate 10 stripped primarily in this manner, thethermosetting resin is partially left rather than being completelyremoved. In order to completely eliminate the residue of thethermosetting resin, the primarily stripped substrate 10 is fed to thephysical/mechanical cleaning unit 14. The physical/mechanical cleaningunit 14 physically and mechanically cleans the primarily strippedsubstrate 10 by a physical and mechanical cleaning method such asbrushing or supersonic wave cleaning. The physically and mechanicallycleaned substrate 10 is cleaned by de-ionized water and then is conveyedfor a rework process.

[0030]FIG. 4 is a flow chart showing a method of removing color filtersand black matrices using a composition for removing a thermosettingresin according to the present invention, and which represents a reworkprocess of a front substrate for a TN mode liquid crystal display panel.

[0031] Referring to FIG. 4, at steps S41 and S42, Cr/CrO_(x) orCr/CrN_(x)/CrO_(x) is entirely deposited on a bare glass substrate andthereafter patterned to form metal black matrices. As a result oftesting the metal black matrices formed in this manner, if it is judgedthat an imperfection has been generated at the metal black matrices, themetal black matrices are dipped into an etchant added with a strong acidin order to be removed. Thereafter, a process of reworking the blackmatrices is carried out at step S43.

[0032] After the metal black matrices are formed, polyacrylate addedwith red, green and blue pigments is entirely deposited on the substrateand then exposed and developed to sequentially form red, green and bluecolor filters at steps S44 to S46. As a result of testing the colorfilters, if it is judged that a problem such as a pattern imperfectionof the color filters has been generated, the substrate provided with abad color filter is loaded into the thermosetting resin eliminatingapparatus as shown in FIG. 3.

[0033] The substrate loaded in the thermosetting resin eliminatingapparatus is exposed to, e.g., submerged in, a composition that includesTMAH and the CARBITOL mixed at a desired component ratio and thereafteris physically and mechanically cleaned as mentioned above. As a result,if the bad color filter is completely removed, then the color filters isagain formed at one of steps S47 to S49. In this case, the color filterrework process may be carried out just after each of the red, green andblue color filters is formed, or alternatively after all of the colorfilters are formed, depending on a time when a bad color filter has beendetected. Finally, an ITO film used as a common electrode is entirelydeposited on the substrate by way of sputtering equipment.

[0034]FIG. 5 is a flow chart showing a method of removing color filtersand black matrices using a composition for removing a thermosettingresin according to another embodiment of the present invention, andwhich represents a rework process of a front substrate for an IPS modeliquid crystal display panel.

[0035] Referring to FIG. 5, at steps S51 and S52, an ITO film used as anearth (or a ground) electrode is entirely deposited on the rear side ofa bare glass substrate. At step S53, resin black matrices made frompolyacrylate are formed on the front side of the bare glass substrate.As a result of testing the resin black matrices formed in this manner,if it is judged that a problem has been generated with one or more theresin black matrices, the substrate is loaded in the thermosetting resineliminating apparatus as shown in FIG. 3. After the bad resin blackmatrices are removed by way of the thermosetting resin eliminatingapparatus, the substrate is again conveyed for a resin black matrixrework process at step S54. After the resin black matrices are formed,red, green and blue color filters made from polyacrylate aresequentially formed at steps S55 to S57.

[0036] As a result of testing the color filters, if it is judged that aproblem such as a pattern imperfection in the color filters has beengenerated, the substrate having a bad color filter is loaded into thethermosetting resin eliminating apparatus as shown in FIG. 3. Thesubstrate in which a bad color filter has been removed of thethermosetting resin eliminating apparatus is again conveyed for thecolor filter rework process at steps S59 to S61. After the color filtersare formed, a protective film is entirely deposited on the substrate insuch a manner to cover the color filters and the resin black matrices atstep S62. Subsequently, as a result of testing the protective film, ifit is judged that a problem has been generated at the protective film,the substrate is loaded into the thermosetting resin eliminatingapparatus as shown in FIG. 3. Thus, the bad protective film is removedof the thermosetting resin eliminating apparatus. After the badprotective film is removed, the substrate is again conveyed for theprotective film rework process.

[0037] As described above, the composition for eliminating athermosetting resin according to the present invention is a mixtureincluding TMAH and the CARBITOL mixed at a desired component ratio. Athermosetting resin is completely eliminated by dipping thethermosetting resin into said composition and then physically andmechanically cleaning it. Thus, the composition according to the presentis suitable for removing a dielectric layer, an organic protectivelayer, an insulating layer, an alignment layer, black matrices and colorfilters, etc. made form a thermosetting resin used in an LCD or othersemiconductor device, and permits a reproduction or a rework of thethermosetting resin film. As a result, it becomes possible to improvethe productivity as well as to minimize the stockpile to be discardeddue to a problem the thermosetting resin.

[0038] Although the present invention has been explained by theembodiments shown in the drawings described above, it should beunderstood to the ordinary skilled person in the art that the inventionis not limited to the embodiments, but rather that various changes ormodifications thereof are possible without departing from the spirit ofthe invention. Accordingly, the scope of the invention shall bedetermined only by the appended claims and their equivalents.

What is claimed is:
 1. A thermosetting resin eliminating apparatus,comprising: a stripping unit to strip a substrate having a layer from athermosetting resin, said stripping unit including a vessel or tub intowhich the substrate is dipped, the vessel or tub containing acomposition of tetra methyl ammonium hydroxide (TMAH), water, and ahygroscopic resin solvent; and a cleaning unit to mechanically clean thestripped substrate using water.
 2. The apparatus of claim 1, whereinsaid hygroscopic resin solvent is CARBITOL.
 3. The apparatus of claim 2,wherein: said TMAH is in a range of about 7-10 wt %; and said CARBITOLis about 50 wt %.
 4. The apparatus of claim 3, wherein said water is ina range of about 43-40 wt %, respectively, relative to said TMAH.
 5. Theapparatus of claim 4, wherein said TMAH is in a range of about 7-8 wt %and said water is in a range of about 43-42 wt %, respectively, relativeto said TMAH.
 6. The apparatus of claim 4, wherein said TMAH is about 10wt % and said water is about 40 wt % relative to said TMAH.
 7. Theapparatus of claim 1, wherein said water is de-ionized water.